Swivel chair



FIG. 1 is a front perspective view of a swivel chair embodying my design;

FIG. 2 is a top plan view of FIG. 1;

FIG. 3 is a front elevational view of FIG. 1; and

FIG. 4 is a right side view of FIG. 3.

The undisclosed rear of the chair is conventional in appearance. 

The ornamental design for a swivel chair, as shown and described. 